Last chance for the oceans?

Marine protection zones may be the only answer as climate change and factory fishing turn the world’s seas into dead zones, warns John Vidal

Clouds of algae spread off the coasts of Latvia and Estonia. Photograph: ESA/AFP/Getty Images

It was summer 2002 when fishermen between the towns of Florence and Lincoln on the north-west Pacific coast of the US began hauling in their pots only to find them full of dead crabs. Tourists then reported finding dead fish and worms washed up on beaches, and divers found the sea bed littered with marine life. It took a team of marine biologists, led by Professor Jane Lubchenco, from Oregon State University to identify giant algal “blooms” as the cause. The sea was full of minute phytoplankton algae that cause oxygen depletion. Quite simply, the water had too little oxygen to sustain life and nothing could survive in what was called “the dead zone”.

“We saw a crab graveyard and no fish the entire day,” Lubchenco said after observing the sea bed from a submersible. “Thousands and thousands of dead crabs were littering the ocean floor, many sea stars were dead, and the fish have either left the area or have died and been washed away… seeing so much carnage was shocking and depressing.”

In the 1960s, fewer than 50 dead zones had been identified worldwide, according to Professor Robert Diaz of the Virginia Institute of Marine Science. But by 2006, he says, there were at least 200, ranging from the Gulf of Mexico and the Pearl River estuary in China, to the Aegean Sea in the Mediterranean and the Mersey estuary in the UK. Last year, more than 400 were found in coastal waters. The phenomena usually last only a few months but they devastate marine life and there is evidence that many are growing and lasting longer.

But the Oregon dead zone was different. Like the others it has returned every year, but Lubchenco and her team of researchers say that it could not have been caused by the run-off of fertilisers from intensive farming like the others. Instead, she says, evidence is mounting that it is being caused by climate change affecting wind and ocean current patterns, dragging up nutrient-rich water from the deep that is low on oxygen. “The evidence is getting stronger,” says Lubchenco. “It’s a further signal that the oceans are under stress. We had never expected to find a dead zone off a coastline that is relatively healthy. It shows a fundamental shift in ocean conditions.”

Dead zones are just the latest phenomenon now putting the planet’s oceans under stress. They rank alongside overfishing, habitat loss, pollution, coral bleaching and climate change as major environmental problems that are transforming the seas and leading to the near collapse of marine systems.

It’s a very far cry from about 100 years ago when the world’s oceans were still, literally, teeming with fish and marine life and no one could believe that the seas could ever be depleted, let alone be taken to the brink of ecological meltdown. Contemporary accounts described breathtaking wildlife phenomena in all the oceans of the world. “Two centuries ago, vast shoals of herring that covered thousands of square kilometres [used to] approach the UK coast to spawn in spring each year,” says Callum Roberts, professor of marine conservation at York University and author of The Unnatural History of the Sea. “We have come to accept the degraded condition of the sea as normal. People put most trust in what they have seen for themselves, which often leads them to dismiss as far-fetched tales of giant fish or seas bursting with life.”

Roberts records the observations of the Irish writer and poet Oliver Goldsmith in the mid-18th century: “When the main body [of fish] is arrived, its breadth and depth is such as to alter the very appearance of the ocean. It is divided into distinct columns, of five or six miles [8-10km] in length, and three or four broad… The whole water seems alive; and is seen so black with them to a great distance, that the number seems inexhaustible,” he wrote.

An early US colonist, William Byrd, tells of the shad and alewife, two fish that are barely seen today. “When they spawn, all the waters are completely filled and one might believe that there is as great a supply [of fish] as there is water. It is unbelievable… indeed indescribable as also incomprehensible what quantity is there,” he reported.

Today, there are still healthy seas but the great majority are relatively quiet. Overfishing, says the UN’s world food and agriculture organisation [FAO], has systematically decimated fish stocks in almost all seas to the point where most of the world’s commercially important fish species have now been fished to capacity or are depleted.

Since 1900, North Atlantic populations of cod, haddock and halibut have fallen by 90%, says the UN. “The haddock, salmon, king crab, bluefin tuna, pollock and mackerel are all overfished, and illegal and unregulated fishing is now eliminating the last of the wild stocks of sharks, lobsters, sea cucumbers and the big fish. In many cases, numbers of some species are down to a mere 2% or 3% of what they were in 1850.”

Last year the UN environment programme charted the alarming decline: “For thousands of years fishing was relatively inefficient, but the situation changed radically… thanks to major advances in the techniques used to catch and store fish. Catches totalled 20m tonnes in 1950, rising to 70m tonnes in 1970 then stabilising between 80m and 90m tonnes. The spectacular increase in 1950-70 was largely due to the development of industrial uses for fish, transforming it into by-products such as meal and oil for use in manufacturing pet food.” In addition, some 20m tonnes of dead fish are believed to be thrown back into the sea every year because they cannot legally be sold, or because they are too small.

Reports of population crashes occur frequently. In the past two months Canadian researchers have predicted the end of all fish caught in the wild by 2048, and the US National Marine Fisheries Service has reported that pollock biomass in US waters was down to 940,000 tonnes from 1.8m tonnes last year. The European Commission says that 88% of EU stocks are now overfished and the UK accepts that only eight of its 47 fisheries are in a healthy state. Other reports have warned that the state of our seas has changed so much over the past 25 years that it could result in fundamental ecological shifts.

The obvious – indeed only – answer, say conservation groups, academics, UN bodies and increasingly even governments, is to stop fishing in vulnerable areas and allow stocks to recover. But this is resented by the politically powerful fishing industries, which dispute the science and warn of unemployment and devastation to communities, and which have been allowed to operate a free-for-all across most of the world’s seas. In addition, politicians have consistently not accepted scientific advice. “The only question is when stocks collapse,” says Roberts.

Protection zones are the most popular alternative, he says. “They should be the ecological underpinning of sea management. One estimate from 2004 put the cost at $12-24bn a year to run a worldwide network of marine reserves covering 30% of all oceans and seas. It seems a lot but they would cost less than the $15-30bn we currently spend on subsidies that encourage excess fishing capacity and prop up exploitation.”

As the situation deteriorates, countries are trying different approaches. The Japanese are giving responsibility to communities, while more radical ideas are coming from Iceland, New Zealand and Australia, says Christopher Costello, professor of environmental economics at the University of California, Santa Barbara. He and two others have published a study of the world’s 11,000 fisheries and found that in all those operating a free-for-all system with normal quotas, fish catches were steadily declining. But in around 150 the fish populations were increasing. All were what are known as “catch-share” fisheries.

Here scientists set a total allowable catch and then individual fisheries are allowed to net a designated percentage of the total amount of a particular species. The total cap on each fish type is adjusted yearly by the government according to how well the species is doing and shares can be bought and sold, becoming more valuable as populations increase. That way the value of the fish rises and over-exploitation is eradicated.

“What we found is that where fisheries were managed with this system, the decline in stocks practically halted. It really brings science to the forefront of the debate,” says Costello. “Under open access, you have a free-for-all race to fish, which ultimately leads to collapse. But when you allocate shares of the catch, then there is an incentive to protect the stock – which reduces collapse. We saw this across the globe.

“We still have time to reinvent the way we manage fisheries and [protect] life in the oceans. I am optimistic for the future. The creation of networks of marine protected areas could reverse this misfortune. But if today’s generation do not grasp the opportunity, tomorrow’s may not get the chance because so many of the species now in decline will have gone extinct.”